The present invention relates generally to electric toothbrushes, and more particularly to an electric toothbrush having a power driven rotary brush.
The use of electric toothbrushes has become very popular as means for achieving simple and efficient overall dental care. Prior art electric rotary toothbrushes provide a rotary brush with axial support on one end. That is, there is not any rotational support on the end of the rotary brush furtherest from the rotary drive connection. As a result of this design, the rotary brush has little stability. In addition, the interconnection of the drive shaft and rotary brush must necessarily be specially designed so that both a drive and mount connection are provided. This special design results in the increased cost of manufacture of the electric rotary toothbrush.
Further, prior art electric rotary toothbrushes generally do not provide for easy removal of the rotary brush or the rotary brush guard. It is advantageous to have an electric rotary toothbrush in which the rotary brush and/or the rotary brush guard can be easily replaced by another rotary brush and/or rotary brush guard so that members of the same family may share a single toothbrush and each have his or her own personal brush.
Prior art toothbrushes that do allow for brush removal are not adequate. By the continued mounting and unmounting of the brush to the motor drive in conventional electric rotary toothbrushes, the interconnection mechanism has been known to wear, resulting in an unstable condition such that the brush cannot be maintained in a rotatably connected mode and in some instances may actually break.
Examples of the prior art include U.S. Pat. No. 3,739,416 to Kurachi in which the rotary brush may be removed only if the brush guard is pivoted or snapped to an open position. In U.S. Pat. No. 3,161,899 to Poizat, the entire arrangement including the stem, rotary brush casing, and rotary can be removed but only as a unit. To remove the rotary brush itself requires the removal of screw 24.
U.S. Pat. No. 3,551,032 to Grossman provides a brush 22 having an elongated stem 20 permanently connected thereto. Sleeve 26 must be opened in order to remove the brush 22 and its elongated stem 20. There is proven need for a rotary electric toothbrush that not only provides rotational support on both ends of its axis, but in addition, can be easily removed and replaced without having to resort to complicated toothbrush housing structure.